Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Job Classification

In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Diagnosis

History: According to the DSM-5, individuals with schizophrenia have at least two of the following characteristic symptoms, each present for a significant length of time during a month (or less if successfully treated): delusions, auditory or visual hallucinations, disorganized speech (e.g., frequent derailment, incoherence), grossly disorganized or catatonic behavior, and negative symptoms (e.g., diminished emotional expression [affective flattening], lack of speech [alogia], or lack of motivation [avolition]). At least one of these symptoms must be delusions, hallucinations, or disorganized speech. (According to the DSM-IV-TR, a single symptom of delusions [if bizarre] or hallucinations [one voice of running commentary or two voices conversing with each other] may substantiate the diagnosis.)

Furthermore, for a significant portion of time since the onset of the disturbance, the level of functioning in at least one major social or occupational area (e.g., interpersonal relations, self-care, work) is markedly below the level present prior to the onset. Signs of the disturbance persist for at least 6 months or more, including at least 1 month of active-phase symptoms such as delusions, hallucinations, disorganized speech, grossly disorganized or catatonic behavior, and negative symptoms; this may include periods of prodromal or residual symptoms characterized by only negative symptoms or an attenuated form of at least two of the following characteristic symptoms: delusions, hallucinations, disorganized speech, grossly disorganized or catatonic behavior, and negative symptoms (e.g., odd beliefs, unusual perceptual experiences).

It is necessary to exclude schizoaffective disorder, depressive or bipolar disorder with psychotic features (and mood disorder, DSM-IV-TR). The disturbance is not attributable to the effects of a substance/medication-induced disorder or another medical condition. In individuals with a history of autism spectrum disorder or a communication disorder of childhood onset, the additional diagnosis of schizophrenia is made only if there are also prominent delusions or hallucinations, in addition to the other symptoms of schizophrenia, for at least 1 month. The individual's developmental background, genetic and family history, current stress factors, level of functioning prior to the illness, and course of the illness may be helpful in ruling out other conditions, such as primary mood disorders with psychotic features.

After a 1-year duration of the disorder, the following longitudinal course specifiers are used only if they are not in contradiction to the diagnostic course criteria: first (single) episode, currently in acute episode, currently in partial remission, or currently in full remission; multiple episodes, currently in acute episode, currently in partial remission, or currently in full remission (with specification if the disorder courses with prominent negative symptoms, DSM-IV-TR); continuous (with specification if the disorder courses with prominent negative symptoms, DSM-IV-TR); and unspecified. Finally, it is recommended to specify the current severity rated by a quantitative assessment of the primary symptoms of psychosis (DSM-5).

According to the DSM-IV-TR subtypes, individuals with the paranoid type of schizophrenia have preoccupation with one or more delusions or frequent auditory hallucinations. Disorganized speech, disorganized or catatonic behavior, or flat or inappropriate affect are not prominent. Individuals with the disorganized type of schizophrenia have disorganized speech, disorganized behavior, and flat or inappropriate affect, all of which are prominent. The criteria are not met for catatonic type. Individuals with the catatonic type of schizophrenia have a clinical picture dominated by two or more of the following features: motoric immobility as evidenced by indefinitely prolonged fixed body postures (catalepsy) with a tendency for the limbs to remain in any position in which they are externally placed by another person (waxy flexibility) or stupor; excessive motor activity that is apparently purposeless and not influenced by external stimuli; an apparently motiveless resistance to all instructions or maintenance of a rigid posture against attempts to be moved (extreme negativism); not engaging in speech (mutism); peculiarities of voluntary movement as evidenced by assuming inappropriate or bizarre postures; stereotyped movements; prominent mannerisms or grimacing; and involuntary imitation of another person’s vocalizations (echolalia) or actions (echopraxia). Individuals with the undifferentiated type of schizophrenia have characteristic symptoms of the disorder, but do not meet the criteria for the paranoid, disorganized, or catatonic type. Individuals with the residual type of schizophrenia have absence of prominent delusions, hallucinations, disorganized speech, and grossly disorganized or catatonic behavior. There is continuing evidence of the disturbance with expression of negative symptoms or an attenuated form of at least two characteristic symptoms of schizophrenia (e.g., odd beliefs, unusual perceptual experiences).

Physical exam: A general physical exam is performed to rule out psychotic disorders due to substance or medication abuse and those associated with underlying physical conditions. The physician also looks for signs of emphysema or lung or heart disease because of the high rate of nicotine addiction in schizophrenics. Subtle neurological abnormalities may be suggestive of schizophrenia. Finally, the physician takes note of the individual's presentation during the exam including dress, mannerisms, behavior, content of speech, and style of relating to others. Individuals with schizophrenia typically exhibit unusual attire, poor hygiene, and may look off to the side as though they are talking to people who are not there.

Tests: No definitive test exists for schizophrenia although neuropsychological tests may aid in diagnosis. Neuroimaging with a computed tomography (CT) scan of the brain may reveal large ventricles characteristic of schizophrenia. Performance of an electroencephalogram (EEG) may also be helpful. Furthermore, clinical laboratory tests are necessary to rule out underlying medical, neurologic, and endocrine disorders that can present as psychoses, such as vitamin deficiencies, uremia, thyrotoxicosis, and electrolyte imbalances. A complete blood count (CBC) and testing for HIV and syphilis should be considered. Additional tests include toxicology screen, antinuclear antibodies (ANA), and urinalysis with culture to rule out the presence of heavy metals and porphyrins.

Note: It must be kept in mind that just because a physical diagnosis cannot be established as the cause of the presenting symptomatology, it does not necessarily mean that the cause is a mental one. That is to say that the presence of medically unexplained symptomatology does not necessarily establish the presence of a psychiatric condition. The first step in identifying the presence of a mental disorder is excluding the presence of malingering and/or of factitious disorder. Although factitious disorder is conscious and purposeful, it is classified as a psychiatric disorder. The strong need for this step is especially true whenever there is a medicolegal context associated with the presenting problem(s). Additionally, using DSM-5 and/or ICD-9-CM or ICD-10-CM, the clinician will find that many presentations fail to fit completely within the boundaries of a single mental disorder. There are systematic ways to go about making psychiatric diagnoses, however.